Human skin undergoes changes with age due to a variety of internal and external factors. Specifically, with respect to the internal factors, the secretion of various hormones that regulate metabolism is reduced, the function of immunocytes and the activity of cells decline, and thus the biosynthesis of immune proteins and structural proteins that constitute a living body is reduced. With respect to the external factors, as the amount of ultraviolet rays reaching the earth's surface is increasing due to destruction of the ozone layer, and as environmental pollution becomes ever more serious, free radicals and reactive oxygen species increase. As a result, skin thickness decreases, wrinkles increase, skin elasticity decreases, the skin color becomes darker, skin troubles frequently arise, and age spots, freckles and dark spots also increase.
As aging progresses, the content and arrangement of collagen, elastin, hyaluronic acid and glycoprotein that constitute the skin are changed or decrease, and oxidative stress occurs due to free radicals and reactive oxygen species. Also, it is known that, as aging progresses or by the action of UV rays, in most cells of the skin, the biosynthesis of cyclooxygenase-2 (Cox-2) producing proinflammatory cytokines known to cause inflammation increases, the biosynthesis of matrix metalloproteinase (MMP) which degrades skin tissue increases due to these inflammatory factors, and the production of nitric oxide (NO) by inducible nitric oxide synthase (iNOS) increases. In other words, due to intrinsic aging that naturally progresses, the activity of cells is reduced, and the biosynthesis of substrates is reduced due to minute inflammation. In addition, due to external factors such as an increase in stress caused by various harmful pollutants and an increase in reactive oxygen species caused by the sunlight, degradation and denaturation are accelerated, and thus the skin matrix is broken and becomes thinner, while various symptoms of skin aging appear. For this reason, many studies on active ingredients that can prevent and ameliorate such aging phenomena are being conducted.
Various factors are involved in determining the human skin color. Among them, the activity of melanocytes producing melanin pigments, the distribution of blood vessels, the thickness of the skin, and the presence or absence of pigments such as carotenoids and bilirubin in the human body, are important.
The most important factor among them is the black pigment melanin which is produced by the action of various enzymes such as tyrosinase in melanocytes. The production of the melanin pigment is influenced by genetic factors, physiological factors associated with hormone secretion and stress, and environmental factors such as UV radiation.
The melanin pigment, which is produced by melanocytes, is a phenolic polymer in the form of a black pigment/protein composite and has useful functions to protect skin organs under the dermis by blocking UV light radiation from the sun and simultaneously to capture free radicals from the skin, thus protecting proteins and genes in the skin.
Melanin produced in the skin due to intrinsic and extrinsic stresses as described above is a stable material and does not disappear until it is discharged to the outside through skin keratinization, even when the stresses disappear. However, if melanin is produced larger than required, hyperpigmentation such as freckles and spots is induced, leading to unfavorable results in the sense of beauty.
These days, women in oriental countries prefer a white and clean skin like white gem and consider this skin as an important beauty standard. For this reason, the demand to solve therapeutic and cosmetic problems for hyperpigmentations has increased.
To satisfy this demand, ascorbic acid, kojic acid, arbutin, hydroquinone, glutathione, or derivatives thereof, or substances having tyrosinase inhibitory activity, have been used in cosmetics or medical drugs. However, the use thereof has been limited due to insufficient whitening effects and various problems, such as skin safety, and formulation and stability, which occur when they are added to cosmetics.
The most important function of the epidermis which is the outermost layer of the skin is to protect the skin from various external stimuli (physical and chemical stimuli such as chemicals, pollutants, dry environment and UV radiation) and to prevent excessive loss of water through the skin. This protective function can be maintained only when the horny layer consisting of keratinocytes are formed normally. The horny layer (stratum corneum), the outermost layer of the epidermis, is formed from keratinocytes and consists of terminally differentiated keratinocytes surrounded by lipid layers. Keratinocytes are the cells generated as a result of the process in which basal cells that continuously proliferate in the lowest layer of the epidermis move up toward the skin's surface while they undergo a series of structural and functional changes. After a given period, old keratinocytes are shed from the skin and replaced by new keratinocytes. This repeated process is called “differentiation of epidermal cells” or “keratinization”. During the keratinization process, keratinocytes form the horny layer, while they produce natural moisturizing factors (NMFs) and intercellular lipids (ceramides, cholesterols and fatty acids), such that the horny layer has firmness and softness to function as a skin barrier.
However, this horny layer can easily lose its functions due to lifestyle factors such as excessive face washing or bathing, environmental factors such as dry atmosphere or pollutants, and intrinsic diseases such as atopy or geriatric skin disease. In fact, due to various factors which have increased recently, more and more people are suffering from dry skin symptoms and various disorders. Thus, in order to keep the skin moisturized at a suitable level, many studies focused on supplying water from outside or preventing loss of water from the body have been conducted. In fact, various kinds of moisturizers having water retention capability have been developed and used mainly in the cosmetic field.
However, as harmful factors to the human body gradually increase in the living environment and an aged population increases rapidly, the turnover rate of the horny layer becomes slower, and the lipid synthesis capability of keratinocytes is reduced, or the division, growth and differentiation of cells in the epidermis become inefficient. As a result, more people have such skin conditions that the quantity of moisturizing factors and lipids is insufficient and the function of the horny layer is not maintained (i.e., the skin barrier function is not maintained).
The abnormality in the division and differentiation of epidermal cells causes various skin diseases, including xeroderma, atopy and psoriasis. Such diseases can be slightly relieved with existing moisturizers having water retention capability only, but it is difficult to expect fundamental cure of the diseases.
Skin disease refers to all disorders occurring on the skin of animals including humans. Inflammatory skin disease refers to a disease that involves a series of clinical signs and symptoms, such as itching, edema, erythema and stripping, due to various stimulating factors which cause a series of inflammatory reactions in the skin epidermis. Known inflammatory skin diseases include atopic dermatitis, contact dermatitis, seborrhoic dermatitis, acne, etc.
For the treatment of the inflammatory skin diseases, antihistamine agents, vitamin ointments and adrenal cortical hormones have been used to date. However, such drugs mostly have temporary effects and show severe side effects in some cases.
Meanwhile, the skin functions as a barrier that protects the body from the external environment. When the skin is wounded, the site of the wound site is filled with blood by natural healing action, and a decrease in platelet granules and the activation of hageman factor is initiated so that a wound healing process takes place. The coagulation of blood is a temporary defensive action that protects exposed wound tissues and provides a basis on which cells can migrate during a healing process (Lee S H A S, Jung S G. Skin Barrier. Seoul: Ryo Moon Gak, 2004).
A wound healing process is generally divided into four phases: inflammatory phase, re-epithelization phase, proliferative phase, and maturation phase. During the inflammatory phase, immune cells appear at the wound site, in which the cells migrated from to the wound site. Then, growth factors, which induce the formation of granular tissue, and signaling substances, are secreted. In a state in which there is no serious infection, the inflammatory phase is generally short (Care KRGf. Advances in wound Care. Seoul: Korea Medical Book Publisher, 2002). The inflammatory phase is essential for the wound healing process.
The proliferative phase occurs similarly to the re-epithelization phase and is characterized in that granular tissues are formed at the wound site (Kubo K K Y. Spongy matrix of hyaluronic acid and collagen as a cultured dermal substitute: evaluation in an animal test. J Artif Organs 2003; 6(1):64-70). Granular tissues are composed of a composition of extracellular matrix elements such as immaturity collagen, fibronectin and hyaluronic acid, as well as fibroblasts and inflammatory cells, and it is important in wound healing that these granular tissues rapidly fill the wound site and have a textured structure. While the exfoliated wound surface is covered by a layer of keratinocytes, a new epidermis is produced and the epithelial layer is reformed. The cells move upward through the wound from the wound edge or the dermal debris of the skin and start to migrate through the scab and living connective tissue.
When re-epithelization of the wound is completed, a series of processes in which the wound area is reduced by an increase in connective tissue and remodeling occur.
Then, during the maturation phase, the coagulated cells and capillary vessels of the tissues in the repair phase gradually disappear, and if such tissues are excessively formed or are not normally degraded, scars will be formed. This is a general wound healing process. Not only rapidly healing a wound, but also healing the wound without side effects or scar, is important in the wound healing process. For this reason, it is more important that tissue cells are filled in a balanced manner while inhibiting inflammation and regulating the expression of growth factors, and efforts to find substances having such effects have been continuously made.
Studies on Chamaecyparis obtusa have been focused on the effects of phytoncide contained in Chamaecyparis obtusa essential oil. Phytoncide is a compound word of “phyton” which means a plant and “cide” which means “exterminate”. It is also called “exterminated by plant” and can be said to be a “woody scent”. It is a substance which is released or secreted by plants to resist pathogens, harmful insects, and molds. If a person takes phytoncide, stress will be reduced, the intestinal and cardiopulmonary functions will be enhanced and the bacteria killing action will also take place. Such phytoncide is composed of phenolic compounds such as terpenes, alkaloids, glycosides, etc., and thus can be extracted using organic solvents. Therefore, the phytoncide of Chamaecyparis obtusa trees is contained in a Chamaecyparis obtusa essential oil extracted from Chamaecyparis obtusa trees.
Although cosmetic compositions for improving skin conditions containing general Chamaecyparis obtusa extracts are known, a Chamaecyparis obtusa polysaccharide and its effects on anti-aging, a reduction in skin wrinkles, an improvement in skin elasticity, skin whitening, skin moisturization, prevention and amelioration of dry skin diseases, anti-inflammation, skin regeneration, and the like are not known.